def save(val, path):
    raise NotImplementedError()

def load(val, path):
    raise NotImplementedError()

def append(val, path):
    raise NotImplementedError()

def compute_or_load(fn, fn_params, path):
    raise NotImplementedError()

def decorator(path):
    raise NotImplementedError()
    
def append(val, path):
    raise NotImplementedError()